If you\u2019ve ever blocked out the Sun with your hand to get a better look at anything, then you\u2019re going to love NASA\u2019s upcoming plan to hunt for habitable worlds.<\/p>\n
Scientists with the U.S. space agency call it the Hybrid Observatory for Earth-like Exoplanets (HOEE<\/a>), an unusual proposal to launch a 328-foot (100-meter) diameter \u201cstarshade<\/a>\u201d into orbit about 108,740 miles (175,000 kilometers) above our atmosphere between Earth and the Moon. The basic premise, as NASA astrophysicist Vladimir Airapetian explained<\/a> it to Universe Today, is to \u201ccreate an artificial eclipse\u201d permitting a powerful ground-based telescope to better see the much weaker glow off of a given distant star\u2019s possibly Earth-like exoplanets.<\/p>\n \u201cThe idea is to build a so-called hybrid observatory where we have a big telescope on the ground that can observe the exoplanetary system in optical light, visible light [\u2026] and then the challenge is to block the star in order to reveal a faint planet a billion times fainter than the star itself,\u201d Airapetian told the site during this year\u2019s Origins 2026 astrobiology conference<\/a> in Paris.<\/p>\n Specifically, Airapetian and his colleagues at NASA and Caltech hope their HOEE orbital will one day essentially piggyback off of the most modern and impressive ground-based telescopes now under construction high in the Atacama Desert above Chile. Projects currently in development, like the European Southern Observatory\u2019s Extremely Large Telescope and the Giant Magellan Telescope\u2014as team lead John Mather argued<\/a> in 2021\u2014could be transformed by HOEE\u2019s starshade into \u201cthe most powerful planet finders yet designed.\u201d<\/p>\n An occult device <\/p>\n According to Mather, an astrophysicist at NASA\u2019s Goddard Space Flight Center, the proposed starshade will need to be lightweight to be practical, both to launch it into orbit and to make it practical to maneuver between the telescope and a distant star\u2019s line of sight. The team\u2019s rough goal has been for HOEE\u2019s starshade payload to weigh in somewhere between 1 and 1.65 tons (1,000 and 1,500 kilograms).<\/p>\n The team has interchangeably referred to the device as an \u201cexternal occulter\u201d and a \u201cflower-shaped occulter.\u201d Once it is completed, the orbital shade could<\/a> have as many as 24 to 48 retractable petals whose shape is dictated by math-heavy hyper-Gaussian principles<\/a> intended to block the greatest amount of light possible. And the HOEE starshade reportedly<\/a> might be tweaked in its orbit by adjustable steady thrusters ejecting hot hydrogen, which would produce no visible emissions and thus reduce the risk of adding unwanted noise to its ground-based telescope partner\u2019s exoplanet imaging.<\/p>\n \u201cInflatable and furled designs under development at NASA Goddard and Jet Propulsion Laboratory\u2019s (JPL\u2019s) Advanced Large Precision Structures (ALPS) lab [will] further support scalable deployment,\u201d the team wrote<\/a> in a 2026 paper on the HOEE for Nature Astronomy.<\/p>\n Phase I complete <\/p>\n According to Airapetian, the HOEE team has already accomplished the objectives, fulfilling its Phase I award from the NASA Innovative Advanced Concepts (NIAC<\/a>) program fund. The project\u2019s Phase II proposal\u2014which would net<\/a> the HOEE team $750,000 to execute two more years of further study on this hybrid observatory-starshade concept\u2014has already been submitted and will be evaluated in the coming months. The team also received funding<\/a> via Caltech\u2019s Keck Institute for Space Studies (KISS).<\/p>\n If approved, the HOEE may cost about a billion dollars, Airapetian told Universe Today. That\u2019s a lot but still a bargain compared to its\u00a0competitor, NASA\u2019s Habitable Worlds Observatory (HWO<\/a>), with its baseline estimated costs hovering<\/a> at around $11 billion.<\/p>\n